Part Part Whole - Part Unknown

Question
Connie has 13 marbles. Five are red, and the rest are blue. How many blue marbles does Connie have?

Direct Modeling
OOOOOOOOOOOOO
OOOOOOOOOOOOO

13 - 5 = ?

Strategy: Counting from
8 blue marbles!







Modeling
OOOOO
OOOOOOOOOOOOO
OOOOOOOOOOOOO

5 + ? = 13

Strategy: Join to
8 blue marbles!



Counting
13 - OOOOO
13 - 5 = ?
Strategy: Countdown from


5 + OOOOOOOO
5 + ? = 13
Strategy: Counting on to


Facts
13 - 5 = ?
Fact known: 3 + 2 = 5//
13 - 3 --> 10 - 2 --> 8
13 - OOO --> 10 - OO --> 8